I.Types of egg on the basis of the amount of yolk

1. Name of Egg: Alecithal
     Amount of Yolk: Negligible of yolk
     Example: Human and other mammals (Placental mammals)

 2. Name of Egg: Microlecithal
    Amount of Yolk: Small amount of yolk.
   Example: Echinoderms(Sea urchin), Branchiostoma, Amphioxus, Marsupials
Types of Egg on the basis of amount of yolk
3. Name of Egg: Mesolecithal
   Amount of Yolk: Moderate amount of yolk.
    Example: Lung-fishes, Amphibians (frogs and toads)

 4. Name of Egg: Macrolecithal or Megalecithal or Polylecithal
    Amount of Yolk: Large amounts of yolk.
     Example: Sharks, Bony fishes, reptiles, and birds 
II. According to the distribution of Yolk 
1. Name of Egg:  Iso lecithal or homolecithal
    Distribution of Yolk: Yolk is evenly distributed.
    Examples: Occurs in alecithal and microlecithal eggs. Sea urchin, amphioxus,marsupials,other mammals
2. Name of Egg: Centrolecithal
    Distribution of Yolk: Yolk at the center of the egg, with cytoplasm around it.
    Example: Insects

 3. Name of Egg: Telotecithal 
    Distribution of Yolk: Yolk is concentrated on one end of the egg, the vegetal hemisphere, with the cytoplasm plus the nucleus concentrated at other ends, the animal hemisphere.
   Examples: Occurs in the mesolecithal and macrolecithal eggs of frogs, toads, birds, reptiles, etc. 
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